Model theory

Basics of Model Theory

Equation form expr-00ae14fd999981ad

c0

Read as: c sub zero

Means: The expression reads: c sub zero. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in the compactness argument for an infinite model.

Equation form expr-00effb3dc62c78b0

In+1(a,b)

Read as: relation I sub n plus one open parenthesis sequence a comma sequence b close parenthesis

Means: The expression reads: relation I sub n plus one open parenthesis sequence a comma sequence b close parenthesis. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-034a69bf5d96f8a8

i=1

Read as: i equals one

Means: The expression reads: i equals one. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-03a9b09b35d993ff

n=0

Read as: n equals zero

Means: The expression reads: n equals zero. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-043111e3d41b47cf

Q=(,<)

Read as: structure Q has domain the rational numbers with the strict order relation

Means: The expression reads: structure Q has domain the rational numbers with the strict order relation. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-043a718774c572bd

s

Read as: s

Means: The expression reads: s. It names the displayed model-theoretic object in the surrounding argument. Its 4 exact source occurrences were reviewed in elementary equivalence and isomorphism and partial isomorphisms and bounded quantifier rank.

Equation form expr-046b4724fc2febf0

an

Read as: a sub n

Means: The expression reads: a sub n. It names the displayed model-theoretic object in the surrounding argument. Its 4 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-04c6cb3677471adb

a1,,anRM

Read as: left angle bracket a sub one comma and so on comma a sub n right angle bracket is in the interpretation of R in structure M prime

Means: The expression reads: left angle bracket a sub one comma and so on comma a sub n right angle bracket is in the interpretation of R in structure M prime. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in substructures.

Equation form expr-05ba6498426fb832

qr(A)n

Read as: the quantifier rank of formula A is less than or equal to n

Means: The expression reads: the quantifier rank of formula A is less than or equal to n. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-0711cb650d84c610

dom(p)

Read as: the domain of p

Means: The expression reads: the domain of p. It denotes a structure domain, a function domain, or the finite sequences drawn from that domain. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-081d0827dce5fc3e

MnN

Read as: structure M is back-and-forth equivalent at level n to structure N

Means: The expression reads: structure M is back-and-forth equivalent at level n to structure N. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-08a31aaffef905c3

xn

Read as: x sub n

Means: The expression reads: x sub n. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-08a7fbd7b687b090

RpQ

Read as: structure R is partially isomorphic to structure Q

Means: The expression reads: structure R is partially isomorphic to structure Q. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-09929e9000f85104

|M|

Read as: the domain of structure M

Means: The expression reads: the domain of structure M. It denotes a structure domain, a function domain, or the finite sequences drawn from that domain. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-09c3a4e1bbdbe5bf

Read as: the rational numbers

Means: The expression reads: the rational numbers. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-0a8619c1e5e29699

SQ

Read as: structure S is isomorphic to structure Q

Means: The expression reads: structure S is isomorphic to structure Q. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-0b73eba3fb667e71

|M|=|M|

Read as: the domain of structure M equals the domain of structure M prime

Means: The expression reads: the domain of structure M equals the domain of structure M prime. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in reducts and expansions.

Equation form expr-0d2e71d5430d87ce

Tan

Read as: formula T superscript a sub n

Means: The expression reads: formula T superscript a sub n. It names the displayed model-theoretic object in the surrounding argument. Its 3 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-0f5269523455caac

s2(xi)=bi

Read as: s sub two open parenthesis x sub i close parenthesis equals b sub i

Means: The expression reads: s sub two open parenthesis x sub i close parenthesis equals b sub i. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-0f54565fa5cee339

xM[s]=s(x)

Read as: the value of x in structure M at assignment s equals s open parenthesis x close parenthesis

Means: The expression reads: the value of x in structure M at assignment s equals s open parenthesis x close parenthesis. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-105e51e805a184da

ar

Read as: a sub r

Means: The expression reads: a sub r. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-10c2f257c944d9b8

a|M|<ω

Read as: sequence a is a finite sequence over the domain of structure M

Means: The expression reads: sequence a is a finite sequence over the domain of structure M. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-11234ea0e731d230

cL

Read as: c is in language L

Means: The expression reads: c is in language L. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in reducts and expansions and substructures.

Equation form expr-11aeab77068a037b

b|M2|

Read as: b is in the domain of structure M sub two

Means: The expression reads: b is in the domain of structure M sub two. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 4 exact source occurrences were reviewed in dense linear orders without endpoints.

Equation form expr-1228b89e6976419f

MM

Read as: structure M is isomorphic to structure M prime

Means: The expression reads: structure M is isomorphic to structure M prime. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-1426674c44e8876f

a1

Read as: a sub one

Means: The expression reads: a sub one. It names the displayed model-theoretic object in the surrounding argument. Its 6 exact source occurrences were reviewed in substructures and partial isomorphisms and bounded quantifier rank.

Equation form expr-148de9c5a7a44d19

p

Read as: p

Means: The expression reads: p. It names the displayed model-theoretic object in the surrounding argument. Its 10 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank and dense linear orders without endpoints.

Equation form expr-1616cefd4bfe7c4c

I0(a,b)

Read as: relation I sub zero open parenthesis sequence a comma sequence b close parenthesis

Means: The expression reads: relation I sub zero open parenthesis sequence a comma sequence b close parenthesis. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-16f30359e94e0291

h(tM[s])=tM[hs]

Read as: h open parenthesis the value of t in structure M at assignment s close parenthesis equals the value of t in structure M prime at assignment h composed with s

Means: The expression reads: h open parenthesis the value of t in structure M at assignment s close parenthesis equals the value of t in structure M prime at assignment h composed with s. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-199649af431f6dc9

N|M|

Read as: N is a subset of the domain of structure M

Means: The expression reads: N is a subset of the domain of structure M. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in substructures.

Equation form expr-19e3ecc2b61fab19

In(a,b)

Read as: relation I sub n open parenthesis sequence a comma sequence b close parenthesis

Means: The expression reads: relation I sub n open parenthesis sequence a comma sequence b close parenthesis. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-1a97e063166f2cca

M2

Read as: structure M sub two

Means: The expression reads: structure M sub two. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in dense linear orders without endpoints.

Equation form expr-1b00a69be11c18ca

s1(xi)=ai

Read as: s sub one open parenthesis x sub i close parenthesis equals a sub i

Means: The expression reads: s sub one open parenthesis x sub i close parenthesis equals a sub i. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-1b16b1df538ba12d

n

Read as: n

Means: The expression reads: n. It names the displayed model-theoretic object in the surrounding argument. Its 24 exact source occurrences were reviewed in reducts and expansions, substructures, the compactness argument for an infinite model, elementary equivalence and isomorphism, partial isomorphisms and bounded quantifier rank and dense linear orders without endpoints.

Equation form expr-1c055d139d0d5aaa

ATh(M)

Read as: formula A is in the theory of structure M

Means: The expression reads: formula A is in the theory of structure M. It identifies a theory, a set defined by a condition, or membership in such a set. Its 4 exact source occurrences were reviewed in the theory of a structure.

Equation form expr-1cb99feaae5823a3

xy(x<yx=yy<x)

Read as: for every x, for every y, open parenthesis x is less than y or x equals y or y is less than x close parenthesis

Means: The expression reads: for every x, for every y, open parenthesis x is less than y or x equals y or y is less than x close parenthesis. It is a complete first-order condition; quantifier scope and connective order are spoken explicitly. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-1da589ed7f3b9bc1

Th(R)

Read as: the theory of structure R

Means: The expression reads: the theory of structure R. It identifies a theory, a set defined by a condition, or membership in such a set. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-1f97d653b7ed2d2b

n+1

Read as: n plus one

Means: The expression reads: n plus one. It names the displayed model-theoretic object in the surrounding argument. Its 5 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-1fe7c7eb47ec94a8

h(tiM[s])=tiM[hs]

Read as: h open parenthesis the value of t sub i in structure M at assignment s close parenthesis equals the value of t sub i in structure M prime at assignment h composed with s

Means: The expression reads: h open parenthesis the value of t sub i in structure M at assignment s close parenthesis equals the value of t sub i in structure M prime at assignment h composed with s. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-2105e6069410f267

a|M1|

Read as: a is in the domain of structure M sub one

Means: The expression reads: a is in the domain of structure M sub one. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-2160509ff364e743

M

Read as: structure M

Means: The expression reads: structure M. It names the displayed model-theoretic object in the surrounding argument. Its 10 exact source occurrences were reviewed in reducts and expansions, substructures, the compactness argument for an infinite model and the theory of a structure.

Equation form expr-220946d9989dcde4

cM[s]=cM

Read as: the value of c in structure M at assignment s equals the interpretation of c in structure M

Means: The expression reads: the value of c in structure M at assignment s equals the interpretation of c in structure M. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-251cc1cf30d62b9a

an<1a

Read as: a sub n is less than sub one a

Means: The expression reads: a sub n is less than sub one a. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-252f10c83610ebca

f

Read as: f

Means: The expression reads: f. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in elementary equivalence and isomorphism and partial isomorphisms and bounded quantifier rank.

Equation form expr-25e3e8b7e278bb51

m>0

Read as: m is greater than zero

Means: The expression reads: m is greater than zero. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in the compactness argument for an infinite model.

Equation form expr-2722d4a09b5fd412

p(fM(a1,,an))=fN(p(a1),,p(an))

Read as: p open parenthesis the interpretation of f in structure M open parenthesis a sub one comma and so on comma a sub n close parenthesis close parenthesis equals the interpretation of f in structure N open parenthesis p open parenthesis a sub one close parenthesis comma and so on comma p open parenthesis a sub n close parenthesis close parenthesis

Means: The expression reads: p open parenthesis the interpretation of f in structure M open parenthesis a sub one comma and so on comma a sub n close parenthesis close parenthesis equals the interpretation of f in structure N open parenthesis p open parenthesis a sub one close parenthesis comma and so on comma p open parenthesis a sub n close parenthesis close parenthesis. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-2821610b26819213

Th(M)={A:MA}

Read as: the theory of structure M equals the set of formula A such that structure M satisfies formula A

Means: The expression reads: the theory of structure M equals the set of formula A such that structure M satisfies formula A. It identifies a theory, a set defined by a condition, or membership in such a set. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-2a0447b022229aa9

R|M|n

Read as: R is a subset of the domain of structure M superscript n

Means: The expression reads: R is a subset of the domain of structure M superscript n. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in reducts and expansions.

Equation form expr-2ceb4df5993cba2b

c1

Read as: c sub one

Means: The expression reads: c sub one. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in the compactness argument for an infinite model.

Equation form expr-2d2b51f442bf96d9

M,sA

Read as: structure M satisfies formula A at assignment s

Means: The expression reads: structure M satisfies formula A at assignment s. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-2d65e3b5556d0619

x¬x<x

Read as: for every x, not x is less than x

Means: The expression reads: for every x, not x is less than x. It is a complete first-order condition; quantifier scope and connective order are spoken explicitly. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-2dc926554b10f1e5

a|M|

Read as: a is in the domain of structure M

Means: The expression reads: a is in the domain of structure M. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-2e7d2c03a9507ae2

c

Read as: c

Means: The expression reads: c. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in elementary equivalence and isomorphism and partial isomorphisms and bounded quantifier rank.

Equation form expr-2eb27f6f4388f1b6

qI

Read as: q belongs to the family I of partial isomorphisms

Means: The expression reads: q belongs to the family I of partial isomorphisms. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-302d3485a34da598

i=1

Read as: i equals one

Means: The expression reads: i equals one. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-336956ed92f44520

hs

Read as: h composed with s

Means: The expression reads: h composed with s. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in elementary equivalence and isomorphism.

Equation form expr-33a9c96304bcc292

|M|

Read as: the domain of structure M

Means: The expression reads: the domain of structure M. It denotes a structure domain, a function domain, or the finite sequences drawn from that domain. Its 3 exact source occurrences were reviewed in substructures, the compactness argument for an infinite model and partial isomorphisms and bounded quantifier rank.

Equation form expr-34da8039f587603d

M1M2

Read as: structure M sub one is isomorphic to structure M sub two

Means: The expression reads: structure M sub one is isomorphic to structure M sub two. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-393fa6d445833984

MM

Read as: structure M is elementarily equivalent to structure M prime

Means: The expression reads: structure M is elementarily equivalent to structure M prime. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-3bd52a5f8fc05fb1

x|M|

Read as: x is in the domain of structure M

Means: The expression reads: x is in the domain of structure M. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-3e23e8160039594a

b

Read as: b

Means: The expression reads: b. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank and dense linear orders without endpoints.

Equation form expr-414fbf909704e19a

pnpn+1

Read as: p sub n is a subset of p sub n plus one

Means: The expression reads: p sub n is a subset of p sub n plus one. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-428890bacf44ce4f

L

Read as: language L prime

Means: The expression reads: language L prime. It names the displayed model-theoretic object in the surrounding argument. Its 4 exact source occurrences were reviewed in reducts and expansions.

Equation form expr-42b8f19ae63d24a4

M

Read as: structure M

Means: The expression reads: structure M. It names the displayed model-theoretic object in the surrounding argument. Its 39 exact source occurrences were reviewed in reducts and expansions, substructures, elementary equivalence and isomorphism, the theory of a structure, partial isomorphisms and bounded quantifier rank and dense linear orders without endpoints.

Equation form expr-43b4349adba93cb9

aa

Read as: finite sequence a followed by element a

Means: The expression reads: finite sequence a followed by element a. It names the displayed model-theoretic object in the surrounding argument. Its 5 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-43d2175a3334d421

n+1=2r

Read as: n plus one equals two times r

Means: The expression reads: n plus one equals two times r. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-449980c431a75564

tM[s]=fM(t1M[s],,tnM[s])andtM[hs]=fM(t1M[hs],,tnM[hs]).

Read as: first row: the value of t in structure M at assignment s equals the interpretation of f in M applied to the values of t sub one through t sub n in M at s; second row: the frozen source prints the value of t in M prime at h composed with s as using the interpretation of f in M. That structure is wrong; the disclosed reader correction uses the interpretation of f in M prime

Means: The expression reads: first row: the value of t in structure M at assignment s equals the interpretation of f in M applied to the values of t sub one through t sub n in M at s; second row: the frozen source prints the value of t in M prime at h composed with s as using the interpretation of f in M. That structure is wrong; the disclosed reader correction uses the interpretation of f in M prime. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism. The frozen second row incorrectly uses the interpretation of f in M. The separately labelled reader MathML and speech use M prime while retaining the source form.

Equation form expr-44af4398f47457e4

h(x)=y

Read as: h open parenthesis x close parenthesis equals y

Means: The expression reads: h open parenthesis x close parenthesis equals y. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-453d4ca47accac68

M,s1A

Read as: structure M satisfies formula A at assignment s sub one

Means: The expression reads: structure M satisfies formula A at assignment s sub one. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-4648c446ad520711

b|N|

Read as: b is in the domain of structure N

Means: The expression reads: b is in the domain of structure N. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 5 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-498b3a5be7e3bfef

xy(x<yz(x<zz<y))

Read as: for every x, for every y, open parenthesis x is less than y implies there exists z, open parenthesis x is less than z and z is less than y close parenthesis close parenthesis

Means: The expression reads: for every x, for every y, open parenthesis x is less than y implies there exists z, open parenthesis x is less than z and z is less than y close parenthesis close parenthesis. It is a complete first-order condition; quantifier scope and connective order are spoken explicitly. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-4a187ef574989a7b

MM

Read as: structure M is elementarily equivalent to structure M prime

Means: The expression reads: structure M is elementarily equivalent to structure M prime. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-4b68ab3847feda7d

X

Read as: X

Means: The expression reads: X. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in elementary equivalence and isomorphism.

Equation form expr-4cedc12a7cb900d8

RL

Read as: R is in language L

Means: The expression reads: R is in language L. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in substructures.

Equation form expr-4d6e78206f377aed

xyx<y

Read as: for every x, there exists y, x is less than y

Means: The expression reads: for every x, there exists y, x is less than y. It is a complete first-order condition; quantifier scope and connective order are spoken explicitly. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-4df11b452df627d0

p0p1p2

Read as: p sub zero is contained in p sub one which is contained in p sub two and the inclusion chain continues in the same way

Means: The expression reads: p sub zero is contained in p sub one which is contained in p sub two and the inclusion chain continues in the same way. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-4f6c7a689e165172

pn+1

Read as: p sub n plus one

Means: The expression reads: p sub n plus one. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-5080d3dfedfa1e07

R=,<

Read as: structure R has domain the real numbers with the strict order relation

Means: The expression reads: structure R has domain the real numbers with the strict order relation. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-51f2b21ec60f5c2b

cicj

Read as: c sub i is not equal to c sub j

Means: The expression reads: c sub i is not equal to c sub j. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in the compactness argument for an infinite model.

Equation form expr-544d9d86fdf219c8

MnN

Read as: structure M is back-and-forth equivalent at level n to structure N

Means: The expression reads: structure M is back-and-forth equivalent at level n to structure N. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-5535619c780145e1

M1pM2

Read as: structure M sub one is partially isomorphic to structure M sub two

Means: The expression reads: structure M sub one is partially isomorphic to structure M sub two. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 2 exact source occurrences were reviewed in dense linear orders without endpoints.

Equation form expr-558a77c65edfbe0c

bn

Read as: b sub n

Means: The expression reads: b sub n. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-5602fb3800556f12

N,bA

Read as: structure N satisfies formula A at assignment sequence b

Means: The expression reads: structure N satisfies formula A at assignment sequence b. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-57281a1889cf91a6

In|M|<ω×|N|<ω

Read as: relation I sub n is contained in the product of the finite sequences over the domains of structures M and N

Means: The expression reads: relation I sub n is contained in the product of the finite sequences over the domains of structures M and N. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-572a63541d07be27

an|M|

Read as: a sub n is in the domain of structure M

Means: The expression reads: a sub n is in the domain of structure M. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in substructures.

Equation form expr-57885e4c75965b23

Γ

Read as: Gamma

Means: The expression reads: Gamma. It names the displayed model-theoretic object in the surrounding argument. Its 4 exact source occurrences were reviewed in the compactness argument for an infinite model.

Equation form expr-57a189d974101797

p(cM)

Read as: p open parenthesis the interpretation of c in structure M close parenthesis

Means: The expression reads: p open parenthesis the interpretation of c in structure M close parenthesis. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-57f24b5799e0d6c5

cM[hs]=cM

Read as: the value of c in structure M prime at assignment h composed with s equals the interpretation of c in structure M prime

Means: The expression reads: the value of c in structure M prime at assignment h composed with s equals the interpretation of c in structure M prime. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-58dee33864546166

s(xi)=ai

Read as: s open parenthesis x sub i close parenthesis equals a sub i

Means: The expression reads: s open parenthesis x sub i close parenthesis equals a sub i. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-5afa20230f875253

n

Read as: n is in the natural numbers

Means: The expression reads: n is in the natural numbers. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-5b63a60fdb499c3a

N

Read as: structure N

Means: The expression reads: structure N. It names the displayed model-theoretic object in the surrounding argument. Its 16 exact source occurrences were reviewed in substructures and partial isomorphisms and bounded quantifier rank.

Equation form expr-5c62e091b8c0565f

P

Read as: P

Means: The expression reads: P. It names the displayed model-theoretic object in the surrounding argument. Its 3 exact source occurrences were reviewed in reducts and expansions, elementary equivalence and isomorphism and partial isomorphisms and bounded quantifier rank.

Equation form expr-5dbd3529e5993e5f

B(x,y)

Read as: formula B open parenthesis x comma bold y close parenthesis

Means: The expression reads: formula B open parenthesis x comma bold y close parenthesis. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-5ebffd07b1fc8460

S

Read as: structure S

Means: The expression reads: structure S. It names the displayed model-theoretic object in the surrounding argument. Its 5 exact source occurrences were reviewed in the theory of a structure and dense linear orders without endpoints.

Equation form expr-606ecf2d3ac02fc7

fL

Read as: f is in language L

Means: The expression reads: f is in language L. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in reducts and expansions and substructures.

Equation form expr-6193864491e4d7b1

NA

Read as: structure N satisfies formula A

Means: The expression reads: structure N satisfies formula A. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 2 exact source occurrences were reviewed in the theory of a structure.

Equation form expr-6216ffaecb7b6fee

a<1a1

Read as: a is less than sub one a sub one

Means: The expression reads: a is less than sub one a sub one. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-6363a064f13f9a94

a1,,anPMiffh(a1),,h(an)PM;

Read as: the tuple a sub one comma and so on comma a sub n is in the interpretation of P in structure M iff the tuple h open parenthesis a sub one close parenthesis comma and so on comma h open parenthesis a sub n close parenthesis is in the interpretation of P in structure M prime semicolon

Means: The expression reads: the tuple a sub one comma and so on comma a sub n is in the interpretation of P in structure M iff the tuple h open parenthesis a sub one close parenthesis comma and so on comma h open parenthesis a sub n close parenthesis is in the interpretation of P in structure M prime semicolon. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-638c289448f33c53

<2=<M2

Read as: the order relation less than sub two equals the interpretation of the order relation less than in structure M sub two

Means: The expression reads: the order relation less than sub two equals the interpretation of the order relation less than in structure M sub two. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-64fb1599d555289c

p0I

Read as: p sub zero is in I

Means: The expression reads: p sub zero is in I. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-6828c4fb95eb4f2c

xTan(x,y)

Read as: there exists x, formula T superscript a sub n open parenthesis x comma bold y close parenthesis

Means: The expression reads: there exists x, formula T superscript a sub n open parenthesis x comma bold y close parenthesis. It is a complete first-order condition; quantifier scope and connective order are spoken explicitly. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-6d7097da4387177a

ai

Read as: a sub i

Means: The expression reads: a sub i. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-6ddf66d8ca32d19f

q=p{a,b}

Read as: q equals the union of p and the singleton set containing the ordered pair a and b

Means: The expression reads: q equals the union of p and the singleton set containing the ordered pair a and b. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-6e15e9a320ee4fb6

R=(,<)

Read as: structure R equals the ordered structure with domain the real numbers and strict order relation less than

Means: The expression reads: structure R equals the ordered structure with domain the real numbers and strict order relation less than. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-6e82ac27792a9ac6

Read as: the real numbers

Means: The expression reads: the real numbers. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-72579d740dd5deb3

a1,,anRM

Read as: left angle bracket a sub one comma and so on comma a sub n right angle bracket is in the interpretation of R in structure M

Means: The expression reads: left angle bracket a sub one comma and so on comma a sub n right angle bracket is in the interpretation of R in structure M. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in substructures.

Equation form expr-74bf6daef0c8b4f8

b1

Read as: b sub one

Means: The expression reads: b sub one. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-75bbcee7ff83e529

p=n0pn,

Read as: p equals the union over all n greater than or equal to zero of p sub n

Means: The expression reads: p equals the union over all n greater than or equal to zero of p sub n. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-798790b3b04fd6ac

I

Read as: the family I of partial isomorphisms

Means: The expression reads: the family I of partial isomorphisms. It names the displayed model-theoretic object in the surrounding argument. Its 5 exact source occurrences were reviewed in dense linear orders without endpoints.

Equation form expr-79960fdc0184c340

p(cM)=cN

Read as: p open parenthesis the interpretation of c in structure M close parenthesis equals the interpretation of c in structure N

Means: The expression reads: p open parenthesis the interpretation of c in structure M close parenthesis equals the interpretation of c in structure N. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-79ee3b0514697b62

pI

Read as: p belongs to the family I of partial isomorphisms

Means: The expression reads: p belongs to the family I of partial isomorphisms. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-7e6d02aef3238a99

p(a1),,p(an)PN

Read as: left angle bracket p open parenthesis a sub one close parenthesis comma and so on comma p open parenthesis a sub n close parenthesis right angle bracket is in the interpretation of P in structure N

Means: The expression reads: left angle bracket p open parenthesis a sub one close parenthesis comma and so on comma p open parenthesis a sub n close parenthesis right angle bracket is in the interpretation of P in structure N. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-7eae821ae4a8e699

a

Read as: sequence a

Means: The expression reads: sequence a. It names the displayed model-theoretic object in the surrounding argument. Its 7 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-7f43b8fe74a47b59

Read as: the empty sequence

Means: The expression reads: the empty sequence. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-810cd2dccf69940b

Th(N)Th(M)

Read as: the theory of structure N is a subset of the theory of structure M

Means: The expression reads: the theory of structure N is a subset of the theory of structure M. It identifies a theory, a set defined by a condition, or membership in such a set. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-8238c028f61fc0f7

A

Read as: formula A

Means: The expression reads: formula A. It names the displayed model-theoretic object in the surrounding argument. Its 15 exact source occurrences were reviewed in reducts and expansions, the compactness argument for an infinite model, elementary equivalence and isomorphism, the theory of a structure and partial isomorphisms and bounded quantifier rank.

Equation form expr-84d7c29eb5648796

M1

Read as: structure M sub one

Means: The expression reads: structure M sub one. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-8687b9c8ed3df547

pq

Read as: p is a subset of q

Means: The expression reads: p is a subset of q. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-8c7a7f6bcfa20e94

MA

Read as: structure M prime satisfies formula A

Means: The expression reads: structure M prime satisfies formula A. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 2 exact source occurrences were reviewed in elementary equivalence and isomorphism.

Equation form expr-8cab39dc469434a8

a|M|

Read as: a is in the domain of structure M

Means: The expression reads: a is in the domain of structure M. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 4 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-8cf1d2a6de92e1c7

xM[hs]=h(s(x))

Read as: the value of x in structure M prime at assignment h composed with s equals h open parenthesis s open parenthesis x close parenthesis close parenthesis

Means: The expression reads: the value of x in structure M prime at assignment h composed with s equals h open parenthesis s open parenthesis x close parenthesis close parenthesis. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-8d2cacefc75ba038

Read as: the empty set

Means: The expression reads: the empty set. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-8dc5e7de60b6f9dc

fM(a1,,an)=fM(a1,,an)

Read as: the interpretation of f in structure M open parenthesis a sub one comma and so on comma a sub n close parenthesis equals the interpretation of f in structure M prime open parenthesis a sub one comma and so on comma a sub n close parenthesis

Means: The expression reads: the interpretation of f in structure M open parenthesis a sub one comma and so on comma a sub n close parenthesis equals the interpretation of f in structure M prime open parenthesis a sub one comma and so on comma a sub n close parenthesis. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in substructures.

Equation form expr-8e35c2cd3bf6641b

q

Read as: q

Means: The expression reads: q. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-8fd0b5c24f4f7eb3

b

Read as: sequence b

Means: The expression reads: sequence b. It names the displayed model-theoretic object in the surrounding argument. Its 5 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-8ffdeed14a973e12

|N|

Read as: the domain of structure N

Means: The expression reads: the domain of structure N. It denotes a structure domain, a function domain, or the finite sequences drawn from that domain. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-9140fbbac1919cbd

MnN

Read as: structure M is elementarily equivalent through quantifier rank n to structure N

Means: The expression reads: structure M is elementarily equivalent through quantifier rank n to structure N. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-92a036d4c0a68d37

p(ai)=bi

Read as: p open parenthesis a sub i close parenthesis equals b sub i

Means: The expression reads: p open parenthesis a sub i close parenthesis equals b sub i. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-9332c3bd965e255c

In(aa,bb)

Read as: relation I sub n holds of the sequence formed by appending a to sequence a and the sequence formed by appending b to sequence b

Means: The expression reads: relation I sub n holds of the sequence formed by appending a to sequence a and the sequence formed by appending b to sequence b. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-93a4cd7eba9e5f60

M

Read as: structure M prime

Means: The expression reads: structure M prime. It names the displayed model-theoretic object in the surrounding argument. Its 11 exact source occurrences were reviewed in reducts and expansions, substructures and elementary equivalence and isomorphism.

Equation form expr-94eb1c931162851e

h(tM[s])=h(fM(t1M[s],,tnM[s]))=fM(h(t1M[s]),,h(tnM[s]))=fM(t1M[hs],,tnM[hs])=tM[hs]

Read as: the frozen first row prints h applied to the value of t in M at s equals h applied to the interpretation of f in M at the component term values, but leaves the outer h unclosed. The disclosed reader correction closes it; the following rows use preservation of f, the induction hypothesis for each component term, and conclude with the value of t in M prime at h composed with s

Means: The expression reads: the frozen first row prints h applied to the value of t in M at s equals h applied to the interpretation of f in M at the component term values, but leaves the outer h unclosed. The disclosed reader correction closes it; the following rows use preservation of f, the induction hypothesis for each component term, and conclude with the value of t in M prime at h composed with s. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism. The frozen first equality omits the closing parenthesis for the outer application of h. The separately labelled reader MathML supplies it while retaining the source form.

Equation form expr-951de0e81c122b91

MA iff MA.

Read as: structure M satisfies formula A iff structure M prime satisfies formula A

Means: The expression reads: structure M satisfies formula A iff structure M prime satisfies formula A. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 1 exact source occurrence was reviewed in reducts and expansions.

Equation form expr-95bf94c81b488aea

tx

Read as: t is syntactically identical to x

Means: The expression reads: t is syntactically identical to x. It states which constant, variable, or compound term the term t is syntactically identical to. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-979c21c3d057d3ab

a,b,c,

Read as: sequence a comma sequence b comma sequence c comma and so on

Means: The expression reads: sequence a comma sequence b comma sequence c comma and so on. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-985a4b89c8dd5a48

MM

Read as: structure M is a substructure of structure M prime

Means: The expression reads: structure M is a substructure of structure M prime. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in substructures.

Equation form expr-986f1f27d63cc6a2

s1(xi)=ai

Read as: s sub one open parenthesis x sub i close parenthesis equals a sub i

Means: The expression reads: s sub one open parenthesis x sub i close parenthesis equals a sub i. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-99a7afc28945ad52

b<2b1

Read as: b is less than sub two b sub one

Means: The expression reads: b is less than sub two b sub one. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-99ac5008bb407d37

=tM[hs]

Read as: equals the value of t in structure M prime at assignment h composed with s

Means: The expression reads: equals the value of t in structure M prime at assignment h composed with s. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-9c63046798238b33

N,s2A

Read as: structure N satisfies formula A at assignment s sub two

Means: The expression reads: structure N satisfies formula A at assignment s sub two. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-9cb6add559e9827b

a1<1a2<1<1an

Read as: a sub one is less than sub one a sub two and the increasing chain continues in order through a sub n

Means: The expression reads: a sub one is less than sub one a sub two and the increasing chain continues in order through a sub n. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-9e104e6e6f84e5fe

bn<2b

Read as: b sub n is less than sub two b

Means: The expression reads: b sub n is less than sub two b. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-9ef57dd225242d99

tc

Read as: t is syntactically identical to c

Means: The expression reads: t is syntactically identical to c. It states which constant, variable, or compound term the term t is syntactically identical to. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-a34b13535dfa2adc

bi

Read as: b sub i

Means: The expression reads: b sub i. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-a3cc0cb59330e6f7

|M||M|

Read as: the domain of structure M is a subset of the domain of structure M prime

Means: The expression reads: the domain of structure M is a subset of the domain of structure M prime. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in substructures.

Equation form expr-a4d6054d41313560

MN

Read as: structure M is elementarily equivalent to structure N

Means: The expression reads: structure M is elementarily equivalent to structure N. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 5 exact source occurrences were reviewed in the theory of a structure and partial isomorphisms and bounded quantifier rank.

Equation form expr-a63ea4e18d5434ea

h(xM[s])=h(s(x))=xM[hs]

Read as: h open parenthesis the value of x in structure M at assignment s close parenthesis equals h open parenthesis s open parenthesis x close parenthesis close parenthesis equals the value of x in structure M prime at assignment h composed with s

Means: The expression reads: h open parenthesis the value of x in structure M at assignment s close parenthesis equals h open parenthesis s open parenthesis x close parenthesis close parenthesis equals the value of x in structure M prime at assignment h composed with s. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-a6c5cb48c610d1ba

R

Read as: structure R

Means: The expression reads: structure R. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in the theory of a structure.

Equation form expr-a7a117f3d210a6d1

b|N|

Read as: b is in the domain of structure N

Means: The expression reads: b is in the domain of structure N. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-a7cc4605f22ea8ed

¬ATh(M)

Read as: the negation of formula A does not belong to the theory of structure M

Means: The expression reads: the negation of formula A does not belong to the theory of structure M. It identifies a theory, a set defined by a condition, or membership in such a set. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-a83dd0ccbffe39d0

I

Read as: I

Means: The expression reads: I. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-aaa9402664f1a41f

h

Read as: h

Means: The expression reads: h. It names the displayed model-theoretic object in the surrounding argument. Its 6 exact source occurrences were reviewed in elementary equivalence and isomorphism.

Equation form expr-ab32642e69fb2b96

LL

Read as: language L is a subset of language L prime

Means: The expression reads: language L is a subset of language L prime. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in reducts and expansions.

Equation form expr-ac0d31a2615b8b66

br

Read as: b sub r

Means: The expression reads: b sub r. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-ad32a18c3f34b508

h(x)=h(y)

Read as: h open parenthesis x close parenthesis equals h open parenthesis y close parenthesis

Means: The expression reads: h open parenthesis x close parenthesis equals h open parenthesis y close parenthesis. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-ad7481becce65291

N¬A

Read as: structure N does not satisfy the negation of formula A

Means: The expression reads: structure N does not satisfy the negation of formula A. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-af35f011a762cdb7

LL

Read as: language L is a subset of language L prime

Means: The expression reads: language L is a subset of language L prime. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in reducts and expansions.

Equation form expr-afd975476ac29b85

x=y

Read as: x equals y

Means: The expression reads: x equals y. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-b253d82d0dd7d895

In(,)

Read as: relation I sub n open parenthesis the empty sequence comma the empty sequence close parenthesis

Means: The expression reads: relation I sub n open parenthesis the empty sequence comma the empty sequence close parenthesis. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-b50bb8940da5b931

L

Read as: language L

Means: The expression reads: language L. It names the displayed model-theoretic object in the surrounding argument. Its 14 exact source occurrences were reviewed in reducts and expansions, elementary equivalence and isomorphism and partial isomorphisms and bounded quantifier rank.

Equation form expr-b6d157c07b7ea123

Γ{cicj:ij}

Read as: Gamma union the set of all inequalities c sub i not equal to c sub j for distinct i and j

Means: The expression reads: Gamma union the set of all inequalities c sub i not equal to c sub j for distinct i and j. It names the displayed model-theoretic object in the surrounding argument. Its 3 exact source occurrences were reviewed in the compactness argument for an infinite model.

Equation form expr-b798b25ce8aef0e2

qI

Read as: q is in I

Means: The expression reads: q is in I. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-b90a027b503e1138

n=2r

Read as: n equals two times r

Means: The expression reads: n equals two times r. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-b968481ad3d20a53

Q

Read as: structure Q

Means: The expression reads: structure Q. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-b9848c4df23f7c87

X={h(x):xX}

Read as: X equals the set of h open parenthesis x close parenthesis such that x is in X

Means: The expression reads: X equals the set of h open parenthesis x close parenthesis such that x is in X. It identifies a theory, a set defined by a condition, or membership in such a set. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-ba37305253caf42e

In(a,b)

Read as: relation I sub n open parenthesis sequence a comma sequence b close parenthesis

Means: The expression reads: relation I sub n open parenthesis sequence a comma sequence b close parenthesis. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-bc552d205810e519

h(cM)=cM

Read as: h open parenthesis the interpretation of c in structure M close parenthesis equals the interpretation of c in structure M prime

Means: The expression reads: h open parenthesis the interpretation of c in structure M close parenthesis equals the interpretation of c in structure M prime. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-bcf2e61a07eb38ac

In+1(a,b)

Read as: relation I sub n plus one open parenthesis sequence a comma sequence b close parenthesis

Means: The expression reads: relation I sub n plus one open parenthesis sequence a comma sequence b close parenthesis. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-be8aaf59162f0d20

nm

Read as: n is greater than or equal to m

Means: The expression reads: n is greater than or equal to m. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in the compactness argument for an infinite model.

Equation form expr-c1080b19cba2171d

pI

Read as: p is in I

Means: The expression reads: p is in I. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-c2f699049ec0fb86

NA

Read as: structure N satisfies formula A

Means: The expression reads: structure N satisfies formula A. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-c40b4b0173218f1f

h:|M||M|

Read as: h is a function from the domain of structure M to the domain of structure M prime

Means: The expression reads: h is a function from the domain of structure M to the domain of structure M prime. It declares the displayed function together with its domain and codomain. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-c425643654d36885

M,hsA

Read as: structure M prime satisfies formula A at assignment h composed with s

Means: The expression reads: structure M prime satisfies formula A at assignment h composed with s. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-c514823f18285213

|M|={a0,a1,}

Read as: the domain of structure M equals the set containing a sub zero comma a sub one comma and so on

Means: The expression reads: the domain of structure M equals the set containing a sub zero comma a sub one comma and so on. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-c5881932f68fbc94

<1=<M1

Read as: the order relation less than sub one equals the interpretation of the order relation less than in structure M sub one

Means: The expression reads: the order relation less than sub one equals the interpretation of the order relation less than in structure M sub one. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-c5d701ec33263c9b

pn+1I

Read as: p sub n plus one is in I

Means: The expression reads: p sub n plus one is in I. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-c626d46f82ba03fe

RS

Read as: structure R is elementarily equivalent to structure S

Means: The expression reads: structure R is elementarily equivalent to structure S. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-c63f9557f464c93a

¬A

Read as: not formula A

Means: The expression reads: not formula A. It is a complete first-order condition; quantifier scope and connective order are spoken explicitly. Its 1 exact source occurrence was reviewed in the compactness argument for an infinite model.

Equation form expr-c89731be03bf2ed7

In(aa,bb)

Read as: relation I sub n holds of the sequence formed by appending a to sequence a and the sequence formed by appending b to sequence b

Means: The expression reads: relation I sub n holds of the sequence formed by appending a to sequence a and the sequence formed by appending b to sequence b. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-c9744b6ef7677f40

I

Read as: the empty set belongs to the family I of partial isomorphisms

Means: The expression reads: the empty set belongs to the family I of partial isomorphisms. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-ca978112ca1bbdca

a

Read as: a

Means: The expression reads: a. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-ca9e13c32046e28a

xyz(x<y(y<zx<z))

Read as: for every x, for every y, for every z, open parenthesis x is less than y implies open parenthesis y is less than z implies x is less than z close parenthesis close parenthesis

Means: The expression reads: for every x, for every y, for every z, open parenthesis x is less than y implies open parenthesis y is less than z implies x is less than z close parenthesis close parenthesis. It is a complete first-order condition; quantifier scope and connective order are spoken explicitly. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-cb304263f4d013a1

cM=cM

Read as: the interpretation of c in structure M equals the interpretation of c in structure M prime

Means: The expression reads: the interpretation of c in structure M equals the interpretation of c in structure M prime. It identifies an interpretation or term value in a named structure and assignment. Its 2 exact source occurrences were reviewed in reducts and expansions and substructures.

Equation form expr-cba83fca6cb88db6

h(tM[s])=h(cM)=cM

Read as: h open parenthesis the value of t in structure M at assignment s close parenthesis equals h open parenthesis the interpretation of c in structure M close parenthesis equals the interpretation of c in structure M prime

Means: The expression reads: h open parenthesis the value of t in structure M at assignment s close parenthesis equals h open parenthesis the interpretation of c in structure M close parenthesis equals the interpretation of c in structure M prime. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-ccc516fb5db93731

RQ

Read as: structure R is elementarily equivalent to structure Q

Means: The expression reads: structure R is elementarily equivalent to structure Q. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-cef3e6639fe132be

M

Read as: structure M prime

Means: The expression reads: structure M prime. It names the displayed model-theoretic object in the surrounding argument. Its 7 exact source occurrences were reviewed in reducts and expansions, substructures and elementary equivalence and isomorphism.

Equation form expr-cefb5bf6ad8b3b09

tf(t1,,tn)

Read as: t is syntactically identical to f open parenthesis t sub one comma and so on comma t sub n close parenthesis

Means: The expression reads: t is syntactically identical to f open parenthesis t sub one comma and so on comma t sub n close parenthesis. It states which constant, variable, or compound term the term t is syntactically identical to. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-cfa587cbef671188

qr(A)

Read as: the quantifier rank of formula A is in the natural numbers

Means: The expression reads: the quantifier rank of formula A is in the natural numbers. It belongs to the finite back-and-forth analysis that connects sequence relations with formulas of bounded quantifier rank. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-d32d67a6c91189ce

(hs)(x)=h(s(x))

Read as: open parenthesis h composed with s close parenthesis open parenthesis x close parenthesis equals h open parenthesis s open parenthesis x close parenthesis close parenthesis

Means: The expression reads: open parenthesis h composed with s close parenthesis open parenthesis x close parenthesis equals h open parenthesis s open parenthesis x close parenthesis close parenthesis. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-d57b0f46efe43717

bi<2b<2bi+1

Read as: b sub i is less than sub two b is less than sub two b sub i plus one

Means: The expression reads: b sub i is less than sub two b is less than sub two b sub i plus one. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-d59286d4fe71a064

MM

Read as: structure M is isomorphic to structure M prime

Means: The expression reads: structure M is isomorphic to structure M prime. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-d62e0e923a9b2c7c

RS

Read as: structure R is elementarily equivalent to structure S

Means: The expression reads: structure R is elementarily equivalent to structure S. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-d6f37f1157dc86de

ai<1a<1ai+1

Read as: a sub i is less than sub one a is less than sub one a sub i plus one

Means: The expression reads: a sub i is less than sub one a is less than sub one a sub i plus one. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-d806ce67cb57e6ad

|M|<ω

Read as: the set of all finite sequences over the domain of structure M

Means: The expression reads: the set of all finite sequences over the domain of structure M. It denotes a structure domain, a function domain, or the finite sequences drawn from that domain. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-d9b1567a52bb6c42

x1

Read as: x sub one

Means: The expression reads: x sub one. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-d9bfe02abd8077a9

MN

Read as: structure M is isomorphic to structure N

Means: The expression reads: structure M is isomorphic to structure N. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-dabd3aff769f07eb

<

Read as: is less than

Means: The expression reads: is less than. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in the theory of a structure and dense linear orders without endpoints.

Equation form expr-dd785660a8e989e6

Th(M)

Read as: the theory of structure M

Means: The expression reads: the theory of structure M. It identifies a theory, a set defined by a condition, or membership in such a set. Its 3 exact source occurrences were reviewed in the theory of a structure.

Equation form expr-dd7d690b005e955c

MA

Read as: structure M satisfies formula A

Means: The expression reads: structure M satisfies formula A. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 3 exact source occurrences were reviewed in elementary equivalence and isomorphism and the theory of a structure.

Equation form expr-de7d1b721a1e0632

i

Read as: i

Means: The expression reads: i. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in elementary equivalence and isomorphism and dense linear orders without endpoints.

Equation form expr-defa158f709798c0

M¬A

Read as: structure M satisfies the negation of formula A

Means: The expression reads: structure M satisfies the negation of formula A. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-e2cae5756a89cef8

L=L{P}

Read as: language L prime equals the union of language L and the singleton set containing P

Means: The expression reads: language L prime equals the union of language L and the singleton set containing P. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in reducts and expansions.

Equation form expr-e2cee4fa1af3fe5e

RN=RMNn

Read as: the interpretation of R in structure N equals the interpretation of R in structure M intersect N superscript n

Means: The expression reads: the interpretation of R in structure N equals the interpretation of R in structure M intersect N superscript n. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in substructures.

Equation form expr-e340dfaaa5d197e9

h(fM(a1,,an))=fM(h(a1),,h(an)).

Read as: h open parenthesis the interpretation of f in structure M open parenthesis a sub one comma and so on comma a sub n close parenthesis close parenthesis equals the interpretation of f in structure M prime open parenthesis h open parenthesis a sub one close parenthesis comma and so on comma h open parenthesis a sub n close parenthesis close parenthesis

Means: The expression reads: h open parenthesis the interpretation of f in structure M open parenthesis a sub one comma and so on comma a sub n close parenthesis close parenthesis equals the interpretation of f in structure M prime open parenthesis h open parenthesis a sub one close parenthesis comma and so on comma h open parenthesis a sub n close parenthesis close parenthesis. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-e3b98a4da31a127d

t

Read as: t

Means: The expression reads: t. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in elementary equivalence and isomorphism.

Equation form expr-e3fc8d5ca7436f60

y|M|

Read as: y is in the domain of structure M prime

Means: The expression reads: y is in the domain of structure M prime. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in elementary equivalence and isomorphism.

Equation form expr-e4bf49ab16382944

PM=R

Read as: the interpretation of P in structure M prime equals R

Means: The expression reads: the interpretation of P in structure M prime equals R. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in reducts and expansions.

Equation form expr-e76589b322685c2d

xyy<x

Read as: for every x, there exists y, y is less than x

Means: The expression reads: for every x, there exists y, y is less than x. It is a complete first-order condition; quantifier scope and connective order are spoken explicitly. Its 1 exact source occurrence was reviewed in dense linear orders without endpoints.

Equation form expr-e77a2a3640dc5e62

PL

Read as: P is in language L

Means: The expression reads: P is in language L. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in reducts and expansions.

Equation form expr-efa51acdf0e7c3c4

L

Read as: language L

Means: The expression reads: language L. It names the displayed model-theoretic object in the surrounding argument. Its 4 exact source occurrences were reviewed in reducts and expansions, substructures and elementary equivalence and isomorphism.

Equation form expr-f014624bc13f0838

|N|={b0,b1,}

Read as: the domain of structure N equals the set containing b sub zero comma b sub one comma and so on

Means: The expression reads: the domain of structure N equals the set containing b sub zero comma b sub one comma and so on. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-f09310eed23df29a

Th(M)Th(N)

Read as: the theory of structure M is a subset of the theory of structure N

Means: The expression reads: the theory of structure M is a subset of the theory of structure N. It identifies a theory, a set defined by a condition, or membership in such a set. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-f13e918fb5415e73

a1,,anPM

Read as: left angle bracket a sub one comma and so on comma a sub n right angle bracket is in the interpretation of P in structure M

Means: The expression reads: left angle bracket a sub one comma and so on comma a sub n right angle bracket is in the interpretation of P in structure M. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-f1431dd70494655a

PM=PM

Read as: the interpretation of P in structure M equals the interpretation of P in structure M prime

Means: The expression reads: the interpretation of P in structure M equals the interpretation of P in structure M prime. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in reducts and expansions.

Equation form expr-f201cf58e38e6fb9

|N|=N

Read as: the domain of structure N equals N

Means: The expression reads: the domain of structure N equals N. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in substructures.

Equation form expr-f2e42e225c740bd9

¬ATh(M)

Read as: the negation of formula A belongs to the theory of structure M

Means: The expression reads: the negation of formula A belongs to the theory of structure M. It identifies a theory, a set defined by a condition, or membership in such a set. Its 1 exact source occurrence was reviewed in the theory of a structure.

Equation form expr-f2f9a15ca6e78219

L

Read as: language L prime

Means: The expression reads: language L prime. It names the displayed model-theoretic object in the surrounding argument. Its 2 exact source occurrences were reviewed in reducts and expansions.

Equation form expr-f4b910f0ec2424f0

M,aA

Read as: structure M satisfies formula A at assignment sequence a

Means: The expression reads: structure M satisfies formula A at assignment sequence a. It asserts truth or failure of truth in the named structure, with the displayed assignment when one is present. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-f50e961536990e1c

M[R]

Read as: the expansion of structure M by relation R

Means: The expression reads: the expansion of structure M by relation R. It names the displayed model-theoretic object in the surrounding argument. Its 1 exact source occurrence was reviewed in reducts and expansions.

Equation form expr-f6b6bdc3fc1d2ad7

MpN

Read as: structure M is partially isomorphic to structure N

Means: The expression reads: structure M is partially isomorphic to structure N. It compares structures by isomorphism, partial isomorphism, or agreement on first-order sentences, exactly as the notation indicates. Its 3 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-f7a15ce91c5701cc

fM=fM

Read as: the interpretation of f in structure M equals the interpretation of f in structure M prime

Means: The expression reads: the interpretation of f in structure M equals the interpretation of f in structure M prime. It identifies an interpretation or term value in a named structure and assignment. Its 1 exact source occurrence was reviewed in reducts and expansions.

Equation form expr-fa2b8d46aafbe3b6

bb

Read as: finite sequence b followed by element b

Means: The expression reads: finite sequence b followed by element b. It names the displayed model-theoretic object in the surrounding argument. Its 4 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-fabcd2f9b64f26db

a|M|

Read as: a is in the domain of structure M

Means: The expression reads: a is in the domain of structure M. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 2 exact source occurrences were reviewed in partial isomorphisms and bounded quantifier rank.

Equation form expr-fb4838846c720493

s2(xi)=bi

Read as: s sub two open parenthesis x sub i close parenthesis equals b sub i

Means: The expression reads: s sub two open parenthesis x sub i close parenthesis equals b sub i. It states the displayed equality, inclusion, membership, or order relation between the named objects. Its 1 exact source occurrence was reviewed in partial isomorphisms and bounded quantifier rank.

Definition of reduct and expansion

A smaller-language structure is the reduct of a larger-language structure precisely when their domains and all shared symbol interpretations agree.

Source

Reducts preserve smaller-language sentences

A structure and its expansion satisfy exactly the same sentences from the smaller language.

Source

Exercise proving preservation under reduct

Unsolved exercise asking for a proof that reducts preserve all sentences of the smaller language.

Source

Expansion by one predicate relation

Defines the notation for expanding a structure by interpreting one newly added predicate as a chosen relation.

Source

Definition of substructure and extension

A substructure has a smaller domain, agrees on constants, restricts functions, and agrees on predicates over its domain.

Source

Overspill theorem for finite models

Arbitrarily large finite models imply the existence of an infinite model.

Source

Finiteness is not first-order definable

No single first-order sentence is true exactly in structures with infinite domain.

Source

Definition of elementary equivalence

Two structures in the same language are elementarily equivalent when they agree on every sentence.

Source

Definition of isomorphism

An isomorphism is a bijection of domains preserving constants, predicates, and functions.

Source

Isomorphic structures are elementarily equivalent

Isomorphism preserves every first-order sentence.

Source

Function-term values before and after an isomorphism

Two aligned equations compare a compound term in M and M prime, with a disclosed wrong-structure correction in the second row.

Source

Inductive equality chain for compound term values

A four-line equality chain proves that an isomorphism carries compound-term values to their values in the target structure, with a disclosed parenthesis correction.

Source

Exercise completing isomorphism invariance

Unsolved exercise asking for the formula case of isomorphism invariance and an accounting of all five isomorphism conditions.

Source

Definition of automorphism

An automorphism is an isomorphism from a structure onto itself.

Source

Exercise on automorphism-invariant definable sets

Unsolved exercise asking to prove that every definable subset is fixed setwise by every automorphism.

Source

Definition of the theory of a structure

The theory of M is the set of all sentences true in M.

Source

The theory of a structure is complete

Every structure decides each sentence, so its theory is complete.

Source

Models of a complete structural theory are elementarily equivalent

Any structure satisfying every sentence true in M is elementarily equivalent to M.

Source

Definition of partial isomorphism

A finite partial function is a partial isomorphism when it satisfies injectivity and the defined constant, predicate, and function preservation clauses.

Source

Definition of partial isomorphism between structures

Two structures are partially isomorphic when a nonempty family of partial isomorphisms has the forth and back extension properties.

Source

Enumerable partially isomorphic structures are isomorphic

For enumerable structures, a back-and-forth family can be assembled into a total isomorphism.

Source

Exercise checking the back-and-forth union map

Unsolved exercise asking to verify that the map constructed in the preceding theorem is an isomorphism.

Source

Partial isomorphism implies elementary equivalence in relational languages

For purely relational languages, partially isomorphic structures agree on every first-order sentence.

Source

Quantifier rank and n equivalence

Quantifier rank measures nesting depth, and n equivalent structures agree on every sentence up to that rank.

Source

Finitely many bounded-rank sentences

A finite relational language has only finitely many sentences of any fixed maximum quantifier rank, up to logical equivalence.

Source

Finite sequences over a structure domain

Defines notation for finite sequences and for appending one element to a sequence.

Source

Recursive back-and-forth relations on finite sequences

Defines relations I sub n first by atomic agreement and then by mutual one-element extensions.

Source

Definition of back-and-forth equivalence at level n

M and N are approximately equivalent at level n when I sub n relates their empty sequences.

Source

Back-and-forth agreement preserves bounded-rank formulas

I sub n implies agreement on formulas of rank at most n, with a converse for finite languages.

Source

Finite back-and-forth equivalence matches bounded elementary equivalence

In finite relational languages, level-n back-and-forth equivalence is exactly agreement through quantifier rank n.

Source

Definition of dense linear ordering without endpoints

Six first-order axioms specify irreflexivity, transitivity, totality, no endpoints, and density.

Source

Cantor isomorphism theorem for countable dense orders

Any two enumerable dense linear orders without endpoints are isomorphic.

Source

Exercise verifying the back property for dense orders

Unsolved exercise asking to finish the Cantor back-and-forth proof by establishing the Back clause.

Source

Cross-reference reference-000491

reference prop:reduct

Source occurrence

Cross-reference reference-000492

reference overspill

Source occurrence

Cross-reference reference-000493

reference defn:iso-const

Source occurrence

Cross-reference reference-000494

reference defn:isomorphism

Source occurrence

Cross-reference reference-000495

reference iso-1

Source occurrence

Cross-reference reference-000496

reference defn:iso-func

Source occurrence

Cross-reference reference-000497

reference defn:isomorphism

Source occurrence

Cross-reference reference-000498

reference iso-2

Source occurrence

Cross-reference reference-000499

reference thm:isom

Source occurrence

Cross-reference reference-000500

reference defn:isomorphism

Source occurrence

Cross-reference reference-000501

reference prop:equiv

Source occurrence

Cross-reference reference-000502

reference thm:isom

Source occurrence

Cross-reference reference-000503

reference defn:isomorphism

Source occurrence

Cross-reference reference-000504

reference thm:p-isom1

Source occurrence

Cross-reference reference-000505

reference prop:qr-finite

Source occurrence

Cross-reference reference-000506

reference thm:p-isom1

Source occurrence

Cross-reference reference-000507

reference thm:p-isom1

Source occurrence

Cross-reference reference-000508

reference thm:cantorQ

Source occurrence

Cross-reference reference-000509

reference thm:cantorQ

Source occurrence

Cross-reference reference-000510

reference remark:R

Source occurrence

Source disclosures